Preparation of visible light active S-doped TiO2 photocatalysts and their photocatalytic activities.

Although titanium dioxide photocatalysts having an anatase phase are a promising substrate for photodegradation of pollutants in water and air, their photocatalytic activities show only under UV light. To utilize solar light which has a large amount of visible light, the development of the photocatalysts whose activities show under visible light is one of the most important strategies. We have succeeded in synthesizing chemically modified titanium dioxide photocatalysts in which S (S4+) substitutes for some of the lattice titanium atoms. They show strong absorption for visible light and high activities for degradation of 2-propanol in aqueous solution and partial oxidation of adamantane in acetonitrile under irradiation at wavelengths longer than 440 nm. The oxidation state of the S atoms incorporated into the TiO2 particles is determined to be mainly S4+ from XPS spectra.